We had heard good things about Trick Flow Specialties 23-degree aluminum heads. If the claim was true that we could expect serious horsepower gains over stock heads and even some aftermarket cast-iron heads, well then we just had to get our hands on a set. There was a project car going together that had a rebuilt stock 350 small-block and it was just right for finding out about "bolt-on" horsepower. With help from Summit Racing Equipment, we worked out a performance package that was reasonable for a street-driven '56 Bel Air and that would allow us to measure the impact of Trick Flow's heads.
Summit sent us a hydraulic Comp Cam and lifters, the Trick Flow Heads with pushrods and rockers, along with the very cool Trick Flow valve covers.
Summit Part Numbers were as follows:1.CCA-12-242-2 Comp Cam2. CCA-812-16 Hydraulic Lifters3. TFS-30400001 Trick Flow 23-degree Aluminum Heads4. TFS-21407850 Trick Flow 7.850 Chrome-moly Pushrods5. TFS-31400510 Trick Flow Rockers, 1.5 Ratio, 3/8-inch Stud6. TFS-31500802 Trick Flow Tall Valve Covers
The engine was built for civilized street performance with approx. 8.5:1 compression, a 650-cfm four bbl., and a TH350. The cam and valvetrain components were installed along with the original Chevy cast-iron heads. Then we did a baseline dyno run at the Primedia Tech Center. It turned out to be a fairly healthy little motor cranking out 215 hp with 300 lb-ft of torque. We had the feeling that it might take quite a bit to raise these numbers noticeably.
Once the Chevy iron heads were replaced with the Trick Flow Aluminum 23-degree set, we rolled the Tri-Five back on the same dyno. What a jolt! By simply bolting on these heads, we went to 270 hp and 341 lb-ft of torque. Wow! It's not that easy to get 55 more horsepower and over 40 lb-ft of torque, but we were looking at the proof. Of course, the car felt quicker and faster, but that seat-of-the-pants feel isn't like looking at the results of a dyno run. Remember, all we changed were the heads, so this is a 25 percent increase in ponies and close to 14 percent in stump-pulling power by just changing parts.
Yes, we know that these parts will set you back several hundred bucks, but there is very little else you can get for that price that will give you this big of a jump in power. It's also great to see the rpm range in which this power is achieved. There is a steady climb of horsepower that brings the maximum on line right around 5,000 rpm. That's a range reasonable for the street and a limit that should keep a small-block alive a long time, especially one with hydraulic lifters.
After our dyno time we spoke to Trick Flow and learned that they spent considerable engineering effort perfecting the runner design. The quality control on manufacture is such that runners and ports are extremely faithful to the design specs, avoiding the need for builders to do CNC-porting or other refinements when they purchase the heads. Our results seem to bear this out as the test results reflect "out-of-the-box" condition of all components. For street-driven cars that are meant to stay civilized these Trick Flow 23-degree aluminum heads are definitely worth a try.
23-Degree Heads for Small ChevyTechnical Specifications: Trick Flow 23-DegreeAluminum Cylinder Heads for SBC